Pivotal stairway systems and method

ABSTRACT

An automated pivoting stairway system that raises and lowers through use of a drive actuator to thereby provide access to above or below floor level areas or between an elevated area and the ground floor. The system may utilize modular sections to allow on-site assembly. The stairway may be pivoted at the top of the stairway by way of a pivot drive lever attached on either side of the top step pivot frame assembly so that access on or off the stairway may be directly off the front end of the stairway, or to either side. A separate frame member may extend from the pivot point along the side of the stairway opening to a predetermined distance. This frame member may serve as the anchor point for the base end mount of the actuator. 
     The actuator controls the length of stroke and the amount of torque that is required to operate the stairway up and down.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 61/195,635, filed 9 Oct. 2008.

BACKGROUND OF THE INVENTION

The present invention relates to systems and methods for stairway configurations, and more particularly to pivoting stairway systems and methods.

For many years, there has been an interest in systems and methods which offer convenient access to storage space on adjacent floors of a building. The search to create this access has resulted in the creation of numerous approaches and types of ladders or stairway systems.

Stowing stairways and ladders that may be retracted, pivoted or folded into ceiling openings are known from several U.S. patents, including U.S. Pat. Nos. 4,541,508, 3,789,955, 6,981,572, and 6,802,392. The access devices described in these patents are generally either pull down retractable or foldable ladders that may be stored in the ceiling of a building, or cable driven and articulating stair units that retract up into the area being accessed.

The foldable or retractable ladder/stairways are typically spring loaded or counterbalanced and may be difficult for users to fold/unfold and pull up/down from the ceiling level before or after use. Further, the steep angle and step design of these devices make them difficult and dangerous to climb, particularly while the user carries bulky objects, such as storage bins. Additionally, known units having an extended counterbalance do not allow the user straight access on and off the unit at the upper level. Rather, the user must sidestep on or off the stairway at the upper level. This may also result in an unsafe operation.

The known cable-driven units also offer several disadvantages to the user. For example, cable-driven units typically utilize multiple pulleys and cable termination points, all of which are subject to wear and/or to service requirements, and even eventual failure which may result in the falling of the unit.

Further, due to these noted design limitations, known foldable or retractable ladder/stairways may not meet building industry standards of a safe staircase design.

Therefore, there is a need for an improved foldable or retractable ladder/stairway system and method of pivoting such a system. Contemplated improvements may include improvement in design and installation, to thereby provide features not found in current stowable stairway systems.

SUMMARY OF THE INVENTION

The present system and method is believed to ameliorate the above mentioned problems through use of an actuator for stairway movement. The present invention may be described as a pivotable stairway that uses an actuator, such as a screw-drive linear actuator, for raising and lowering the stairway. The present arrangement results in secure, stable and safe to use systems and methods, with the present invention herein described generally as an actuator driven pivoting stairway [ADPS].

The main object of the actuator driven pivoting stairway is to provide a stable, safe and efficient access from one floor level to another, whether the floor is above or below, or the installation is inside or outside the main building.

The unique design of the ADPS provides the user with facile, straight off and straight on access at the entrance or exit of the stairway. The straight off and on access may be provided at either or both the top and bottom of the stairway, and eliminates the need to sidestep on or off the stairway, as in known arrangements. This feature may be accomplished through the use of an actuator which may be mounted to the stairway on one or both sides of the stairway unit.

A preferred embodiment of the present invention uses a screw-drive linear actuator to create the motion and force to raise and lower the pivoting stairway. With the actuator drive creating the pivoting movement for the stairway, there is no need for other mechanical devices, such as cables, pulleys, counterbalance weights or springs, although they may be used to supplement the actuator.

A preferred method of installation of the invention includes mounting an actuator to a pivot bracket on one side of the stairway, providing a drive lever, and mounting the drive lever to the upper floor. It is to be understood that other methods of installation are possible, depending on the configuration of the installation site.

It is also envisioned that the invention may include upper and lower load limit safety sensors that control the screw drive actuator, to maintain operational control and safety. Further, the actuator may have a brake mechanism built into the design of the unit, to thereby hold in place and stop the up or down movement of the device whenever power is no longer directed to the unit.

A preferred method of construction of the invention includes an actuator driven pivoting stairway in which the stairway is manufactured using modular components. The use of modular a design permits the combination of multiple components from stock, pre-assembled sections to accommodate different installation requirements. A modular system offers greater flexibility in assembly, economical shipping, and increased safety in assembly due to the reduced weight of the modular components as compared to a single piece unit. Further, the modular design of the present invention allows in-field assembly to fit a full range of ceiling height measurements, without sacrificing the strong, stable, safe and secure integrity of the entire stairway unit. Alternatively, the ADPS may be completely or partially assembled without the use of modular components.

The invention offers many benefits including, but not limited to, transforming vacant space into a usable storage or living area, offering additional access points to another floor, and freeing up floor space traditionally encumbered by a permanently located staircase.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the actuator driven pivoting stairway (ADPS) system in the down, or usable position. This view illustrates that the top step may be level with the upper floor plane.

FIG. 1A is a perspective view of the system illustrated in FIG. 1 and showing movement into the stowed position.

FIG. 2 is a perspective view of the embodiment shown in FIG. 1, but illustrating the ADPS in the up or stowed position.

FIG. 3 is a front view of the embodiment shown in FIGS. 1 and 2, and showing the ADPS in a down position, and illustrating a straight on-off access at an upper level.

FIG. 4 is a perspective view of various modular elements for use in a preferred embodiment.

FIG. 5 is an exploded view of an embodiment of the present invention

FIG. 6 is an exploded view of an embodiment of a pivot bracket assembly mounting.

FIG. 7 is an exploded view of an embodiment of an actuator rod pivot assembly.

FIG. 8 is a fragmentary, partially exploded view of one embodiment of the actuator pivot mounting assembly.

FIG. 9A is a fragmentary, exploded view of one embodiment of a step rail assembly.

FIG. 9B is an enlarged, fragmentary view of a step profile.

FIG. 10 is a perspective view of an alternative, articulated, actuator driven pivoting stairway (ADPS).

FIG. 11 is a perspective view of the embodiment of FIG. 10, but showing the hand rail rotated into a collapsed position in readiness for segment rotation.

FIG. 12 is a perspective view of the embodiment shown in FIGS. 10 and 11, but illustrating section rotation.

FIG. 13 is a perspective view of the embodiment shown in FIGS. 10-12, but illustrating the system in the up or stowed position.

FIG. 14 is a fragmentary, partially exploded view of an alternative embodiment of a stairway section, and showing an access panel and removable stair treads.

FIG. 15 is an illustration of one embodiment of an outer panel assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.

I. Stowable Stairway System

The present invention may be generally described as a stairway system 10 to provide access between spaces on two or more different levels of a building or other multi-level structure. Specifically, the invention is directed to a stairway system 10 having means for retracting into the ceiling or floor 12 of a level. Means may include use of an actuator 14 as part of the system 10 (See FIGS. 1 through 15).

As will be apparent, the systems and methods of the present invention allow installation of the stairway system 10 without drilling of pivot holes in the existing floor joists or frame 16 at the top 18 of the stairway system 10, as is required by known apparatuses. In a preferred embodiment of the invention, the stairway system 10 is pivoted at the elevated top end 18 (see for example FIG. 1, although it is to be appreciated that the stairway system 10 may be pivoted at the lower end 20 as well. The invention allows the stairway system 10 to be stored completely or partially into the ceiling or floor space 12. It should be noted the invention could be designed to rest just below the ceiling or floor or above the ceiling or floor, should that be preferred.

As may be observed particularly in the view of FIG. 3, a preferred embodiment of the stairway system 10 is designed such that the width W of the stairway system 10 fits between standard trusses or floor joists 16 that are set on a 24″ center. It should be noted however that the stairway system 10 may be designed to fit any desired opening width.

As may be seen generally in FIGS. 1, 1A, and 2, a preferred embodiment of the stairway system 10 includes a stairway 22, an actuator 14 having a base end 24 and a rod end 26, and a drive lever 28 pivotally connected to the rod end 26 of the actuator 14. A driven pivot bracket 30 is adapted to be attached to the upper floor or framework 16 on one side of the stairway 22, with a first end 32 being connected to the base end 24 of the actuator 14 and a second end 34 being attached to the drive lever 28. A non-driven pivot bracket 36 is adapted to be attached to framework 16 on an opposite side of the stairway 22.

As mentioned, the systems and methods of the present invention allow installation without drilling of pivot holes in the existing floor joists or frame 16 at the top 18 of the stairway 10. In contrast, a pivot rod 38 is seated in the pivot brackets 30, 36 located on each side of the stairway 22 opening (See FIG. 6). Although the method of installation shown in the Figures is a preferred method, it is to be understood that other methods of installation may include attaching the stairway system 10 directly to the floor 12 above or to the frame members 16. In its present form, the stairway system 10 allows the positioning of the stairway 22 between the ceiling trusses or floor joists 16.

With attention now to FIG. 6, the pivot assembly 40 may be seen. As illustrated, a preferred pivot assembly 40 may be mounted just below the top step 62 of the stairway 22. As may be further observed, the pivot assembly 40 may include a pivot crosstie 42, driven pivot bracket 30, non-driven pivot bracket 36, and drive lever 28. The pivot crosstie 42 may be attached to a selected side rail 70 top 44 using brackets 46 as added support. The drive lever 28 may be mounted to the bracket 46 and the side rail top 44.

As shown, the non-driven pivot bracket 36 may be assembled though the brackets 46, pivot crosstie 42, side rail top 44 and the drive lever 28, and connected to the driven pivot bracket 30.

In the present form of the invention, the stairway motion may be created by the use of an actuator 14, such as the screw drive linear actuator shown. It should be noted that the actuator 14 could be of a design other than screw driven. The actuator 14 might be piston driven, it might be chain driven, it might be pneumatic in design, and it might be hydraulic in design, as non-limiting examples. A preferred actuator 14 includes a gear motor drive that rotates a screw rod (not shown) which is housed within the unit itself. As may be further observed with reference to FIG. 7, the drive unit may be attached to the drive lever 28 at the rod end 26 of the linear actuator 14 by use of a clevis type or suitable positive connector, such as direct couple, spring loaded connector, rigid connection, as non-limiting examples. As viewed in FIG. 8, the base end 24 of the actuator 14 may be connected by a pivot pin 50 and the pivot mounts 52 on the driven pivot bracket 30. The actuator 14 may be further provided with means for manual operation, if desired. Access 90 for manual operation is shown in phantom. Although a preferred arrangement has been shown and described, it is to be understood that the actuator 14 could be installed in any manner that allows the connection of one end of the actuator to the framing or flooring, and the other end attached to the unit in such a manner as to afford the system 10 to operate correctly, as floor constructions may vary.

With reference now to FIG. 1A, system 10 operation may be viewed. The actuator 14 is extended in the direction of arrow A; the force pushes the drive lever 28 in the direction of arrow B away from the actuator base. This action rotates the pivot crosstie 42 (not seen in this view) and the rest of the pivot assembly 40 (see FIG. 6) in the direction of arrow B. As the push force is applied to the drive lever 28 of the pivot assembly, the stairway 22 raises in the direction of arrow C to the upper or horizontal position as viewed in FIG. 2. To lower the stairway 22, the actuator 14 is retracted; the pull force allows the pivot assembly 40 to rotate in the opposite direction, which thereby lowers the stairway 22 to the usable position shown in FIG. 1. When the system 10 is pivoted into the fully raised position illustrated in FIG. 2, the unit may then be parallel with the upper floor 12.

The actuator 14 may also be operated with a power supply enabling the unit to be operated with a battery (not shown) during a power outage situation, for example.

A preferred embodiment may utilize a power supply consisting of a 12V DC motor 56 which is supplied current through a 120 V AC converter 54. It should also be noted that the invention could be designed to operate on a variety of power systems such as 12V DC, 24 V DC, 120V AC, and 240 V AC, as non-limiting examples. Alternatively, power could be supplied and/or generated using other methods such as solar, hydroelectric, battery, and wind, as non-limiting examples.

In a preferred embodiment of the system 10, the actuator 14 may be provided with one or more of a breaking system, current load limits, as well as separate circuits for control operations. The stairway 22 may also be equipped with limit switches 58 for upper and lower stops as well as sensors for obstruction detection (not shown).

As may be observed, the actuator 14 and drive lever 28 are preferably mounted to one side of the stairway 22 step area, giving the user a clear and straight approach to the steps 60. Further, the top step 62 may be easily exited or entered from the upper level floor, and all steps 60 may be large enough to provide for easy and comfortable use.

It is preferred that the present system 10 be primarily fabricated with extruded, modular aluminum metal parts. The illustration of FIG. 4 shows various interchangeable stairway 22 lengths that may be used with the system top section 64 and bottom section 66. Although extruded aluminum is the preferred material, it should be noted that other types of materials, sufficient to withstand the stresses inherent in its use and design, may be used in the construction of the invention such as plastic, resins, other metals, composites, and woods or other natural materials, as non-limiting examples.

As seen generally in FIGS. 1-3 and 5, the stairway 22 may be equipped with handrails 68 on one or both sides. FIG. 5 illustrated the manner by which the handrail 68 may be attached to selected side rail sections 70. Since the present system 10 allows straight on and off of the stairway 22, the handrail 68 may be mounted on either side, or both sides of the stairway 22, without causing any obstruction or safety hazard. The handrail 68 is preferably made of tubular metal that is mounted to the stairway 22 for personal safety; however the handrail 68 may be manufactured from different materials such as plastic, composites, solid metal, wood, etc, and may be mounted in different locations. Further, the handrail 68 may be constructed in other configurations than tubular, such as flat, and square, as non-limiting examples.

The present system 10 allows the handrail 68 remain attached to the stairway 22 even while in the upper, stowed position (See FIG. 2). Thus, the handrail 68 does not need to be collapsed or folded out of the way, as is required by other known handrail assemblies. Although it should be noted that the handrail 68 may be designed in such a manner as to be folded, collapsed, or in other manner retracted, if desired.

The present system 10 may also include a fire proof cover material on a bottom surface 72 of the stairway unit (see FIG. 15). Fire proof material can be, but is not limited to, drywall, metal or other suitable materials that also allow the user to paint, texture, or otherwise match the surface finish to create an eye pleasing structure that may compliment the existing ceiling surface. The system may further be provided with a pre-installed fire brush 74. As may be observed particularly in FIG. 1, a fire brush 74 may be used to create a fire stop surface between the upper and lower floors 12 at the stairway opening 76. It should be noted that although the present drawings illustrate use of a fire brush 74, any type of fire resistant material which meets local building codes and which fills the space along the sides of the stairway opening 76 may be used, such as an interlocking magnetic material, flexible plastic or other suitable material, or fabric buffer, as non-limiting examples.

The present system 10 may be equipped with leveling devices 78 on the bottom section 66 of the stairway 22 that rest against the floor to allow for uneven surfaces when the stairway 22 is in the lowered position. These leveling devices 78 may be designed to incorporate one or more of limit switches, safety stops, and operation warning lights, as non-limiting examples.

II. System Controls

The control for the present invention may be mounted off the stairway unit 22 and may be wired to the actuator 14 via a whip or wire type cord 80 connection. A preferred control operator in the form of a removable momentary key operated switch 82 may be seen in FIGS. 1, 1A, and 2. The preferred switch 82 is designed to be activated and operator attended for system 10 and stairway 22 operation, to thereby prevent unintentional movement of the stairway 22. Use of the removable key ensures that the operator can control by whom and when the stairway 22 is used. Although this switch is preferred, other types and configurations of control units could be employed, such as pushbutton, push-pull, and lever controls, and electronic, wireless remote control, audio recognition, and optical communication, as non-limiting examples.

III. Modular Design

As discussed previously and shown in FIGS. 4 and 5, the present invention may be designed in modular sections. The modular design may incorporate fabricated stock parts. The steps 60, brackets 46, side rails 70, joint plates 84, covers 86, end caps 88, and additional sub assemblies may be designed as bolt together assemblies. Although modular construction is preferred for its ease of use and efficiency, the system 10 may be assembled using glue, rivets, thermal welding, electronic welding, sonic welding, or fused together with light energy, for example.

The contemplated modular construction of the present system 10 provides manufacturing and installation advantages. For example, rather than one solid welded stairway 22 that must be custom built to each installation, the modular design may use preassembled sections that can be assembled in the field to allow a full range of sizes and installation options. In addition, the modular design of the present invention reduces assembly, shipping, and handling costs as compared to one piece units. It should be noted however, that the present invention is not limited to modular construction and may be manufactured without the use of modular components. It may be built on site or it may be built in one piece and transported to the installation location. The present system 10 may be entirely custom fabricated.

IV. Articulated System

With attention to FIGS. 10-13, an articulated stairway system 10A may be seen. As may be observed, the stairway system 10A may be provided with hinges 92 or other acceptable means to thereby hingedly connect adjacent stairway sections 22. The articulated design permits the unit 10A to be collapsed prior to retraction into the stairway opening. The unique collapsible design allows the system 10A to be stowed into a stairway opening 76 having a length L less than the total, extended stairway length L′(see FIG. 13). This capability frees up floor space on the upper level and provides a more compact storage unit.

As seen particularly in FIG. 10, the articulated system 10A may include a top section 64 a bottom section 66 and at least two stairway sections 22. The stairway sections 22 are pivotally connected in an acceptable manner, as by the hinges 92 shown, for example. The hinges 92 may be provided with suitable locking mechanisms 94 to safely retain the stairway sections 22 in the extended position while in use. A handrail 68 may be optionally provided.

A method of stowing the articulated system 10A may be seen in FIGS. 11-13. As shown, and if provided with handrails 68, handrails 68 are moved in the direction of arrows D to rest against the stairway sections 22. As seen in FIGS. 12 and 13, stairway section 22 is rotated in the direction of arrow E to a position to overlay section 22. The stacked unit is then rotated in the manner previously described, into the stairway opening 76. FIG. 13 illustrates the articulated system 10A in the stowed position and shows the relative economy of storage length, with length L being shorter than L′, the total extended length.

V. Methods of Use

In use, the both the articulated and non-articulated systems 10, 10A may be operated in a variety of ways with user controls, as previously described. When the operator desires to lower the stairway 22, a removable key (not shown) may be inserted into the control switch 82. The key may be turned to provide a control signal to the actuator 14. The actuator 14 then provides the force to the drive lever 28, and the stairway 22 pivots upward or downward.

Sensors and other devices, as previously described, may be automatically activated during the raising and lowering process to control the safe and accurate raising and lowering of the stairs. Once down, the stairway may be used. The process may be reversed to raise the stairway to the stowed position.

VI. Methods of Installation

The ADPS may be configured to be installed in a variety of configurations, depending on the installation area, and may be installed in new construction, or after construction is complete (i.e., retrofit). The following example describes methods of installation for a retrofit application:

Selecting a location for installation; removing an area of ceiling sufficient for the system 10, 10A; mounting the pivot assembly 40 to the floor joists 16; coupling modular sections 22, 64, 66 of the stairway 22 together in a predetermined manner and sufficient in height to reach from the ceiling to the floor at the desired angle; coupling the assembled stairway 22 to the pivot frame assembly 40; mounting the actuator 14 and driven pivot bracket 30 to the joist 16 and to the drive lever 28; and coupling the control system to a power source, and to the actuator assembly.

The systems 10, 10A of the present invention may be further provided with a modified top section 64A. Modified top section 64A is adapted to permit emergency access to the upper level in the event of power or other mechanical system failure. As seen in FIGS. 14 and 15, the modified top section 64A may include a removable panel 94, to thereby allow access to treads 60. Treads 60 are attached to side rails 70 by way of accessible bolts 98 which may be unfastened to thereby remove treads 60 from section 64A. Access through the top section 64A is then possible.

The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 

1. A pivoting stairway comprising: a stair having a pair of side rails, a plurality of treads extending between the side rails, a stair top and a stair bottom; a pivot member upon which the stair is pivotally mounted; a linear actuator having a first end and a second end, said linear actuator providing force to raise and lower the pivoting stairway.
 2. The stairway of claim 1 further including a pivot bracket and a drive lever, wherein said first end of said actuator is pivotally connected to said pivot bracket, and said second end of said actuator is pivotally connected to a first end of said drive lever.
 3. The stairway of claim 2 wherein said stair top is connected to a second end of said drive lever.
 4. The stairway of claim 3 wherein said pivot bracket further includes at least one bracket plate said bracket plate being adapted to support said pivot member.
 5. The stairway of claim 1 further including a power source in communication with said actuator to thereby drive said actuator.
 6. The, stairway of claim 5 further including at least one'sensor, the sensor being in communication with said power source to thereby control said actuator.
 7. A method of installing a pivoting stairway including: providing a stair having a pair of side rails with a plurality of treads extending between the side rails, a stair top and a stair bottom; selecting a predetermined installation location said location having at least one support member; providing a pivot assembly, said assembly including at least a pivot bracket, a drive lever and a pivot member; mounting said pivot assembly to said support member; coupling said stair to said pivot assembly; providing an actuator; coupling said actuator to said drive lever whereby the actuator's driving of the drive lever rotates the stair about the pivot member.
 8. An articulated pivoting stairway comprising: a plurality of stair sections, each one of said plurality of stair sections being pivotally connected to an adjacent one of said plurality, each one of said plurality of stair sections having a pair of side rails, a plurality of treads extending between the side rails, a stair top and a stair bottom; a pivot member upon which the stairway is pivotally mounted; a linear actuator having a first end and a second end, said linear actuator providing force to raise and lower the pivoting stairway.
 9. The stairway of claim 8 further including a pivot bracket and a drive lever, wherein said first end of said actuator is pivotally connected to said pivot bracket, and said second end of said actuator is pivotally connected to a first end of said drive lever.
 10. The stairway of claim 9 wherein one of said plurality of stair sections includes a stair top, said stair top being connected to a second end of said drive lever.
 11. The stairway of claim 10 wherein said pivot bracket further includes at least one bracket plate said bracket plate being adapted to support said pivot member.
 12. The stairway of claim 8 further including a power source in communication with said actuator to thereby drive said actuator.
 13. The stairway of claim 12 further including at least one sensor, the sensor being in communication with said power source to thereby control said actuator. 